The success of lawn grass relies significantly on the health of soils and root zones, where soil texture determines the rate of infiltration and percolation downward through the root zone. The rate at which water moves downward determines how much soil nutrients are absorbed through the roots. Soil with a rapid percolation rate will not hold nutrients within the soil long enough for 100% availability for the plant roots.
Slow percolation rates can cause nutrients to stay too long in the root zone and become toxic by over-fertilization. Regardless of soil type or texture, improvements can always be made for enhanced grass growth. Modifications are required to elevate lawn grass to a higher standard, with the following practices aimed at improving soil health.
1. Using Soil Tests to Diagnose Nutrient Deficiency & Other Ailments
Nutrients are required for optimal growth from the soil, and testing its composition provides crucial information for taking corrective actions. Knowing what is within the soil dictates what the soil has, what it needs, and what is in deficient or excess amounts. The results will tell the future of our lawns by what they have been eating and what they need to eat to thrive.
A soil test can determine soil pH and recommendations for corrective actions to raise or lower it to be between 6.0 and 7.0. Soils can vary in acidity or alkalinity on the pH scale, requiring soil amendments to enhance nutrient absorption by the roots. Extreme pH levels on either end of the scale can affect characteristics such as color, turf hardiness, and survival during drought and other environmental stresses. While soils generally remain stable annually, conducting a soil test annually or every two years is recommended. The appropriate action to restore pH balance involves adding lime or elemental sulfur.
2. Aeration Methods for Soil Compaction & Nutrient Uptake
Two different aerification methods are performed on lawn grass: core aeration and solid tine aeration. Core aeration removes a core cylinder, or plug, from the soil to a minimum depth of 3” - 4”. Coring tines can also be utilized with larger or smaller diameters. The coring tines enter the root zone soil and pull the soil core out. Removing actual soil matter creates pore space on 2” - 6” spacing.
Professional turf management aerators can adjust ground speed and the desired spacing between core holes. Compaction reduction is accomplished when core aeration is practiced regularly in a lawn maintenance program, regardless of the spacing. Water droplets, atmospheric oxygen, UV rays, and nutrients can penetrate directly into the root system through the core openings within the soil. The longer the core openings are available, the better the turf will perform.
Solid tine aeration uses a non-coring tine that penetrates that soil surface to the depth of 3” - 4” and does not remove a soil plug. Water, air, and UV rays can enter these openings but close more rapidly. The soil is squeezed and compressed within the soil profile, contributing to internal compaction. Eventually, the openings created with the solid tine penetration close and cause infiltration and percolation to slow. Solid tine aeration is mainly used for temporary relief and not as a long-term plan to improve soil.
Core aeration removes thatch and also helps reduce thatch layers over ½”, making it essential for thatch reduction alongside dethatching. Small thatch sections are removed with the core plug, and oxygen enters the openings to decompose dead organic matter. Solid tine aeration will allow oxygen into the thatch layer, but it will not remain open as long as core aeration.
3. Topdressing the Lawn
Core aeration followed by topdressing serves many beneficial purposes for lawn grass, as the topdressing sand and topsoil contain microbes that become active within the thatch layer, consuming dead organic material and reducing its thickness. The particle size within the topdressing material is screened and processed to a coarse or medium fine texture. These specific particle sizes fall into the core openings, forming a porous column where water, air, and nutrients can follow downward into the root zone.
Particle sizes with fine texture and angular shape soil particles bond and reduce infiltration and percolation rates. Reducing these rates affects the downward travel speed of nutrients, leading to shallower rooting, which poses challenges for roots to survive once summer arrives and hotter days arise.
When leveled over the surface of lawns, topdressing fills low spots, creating a smoother lawn and preventing standing water for long periods. Core aeration in coordination with topdressing aids internal drainage and reduces surface runoff.
4. Benefits of Verticutting and Dethatching
Verticutting and dethatching is a process in which dead thatch is sliced with star-shaped blades rotating with high rpm that grind and cut thatch where it is collected and removed on the surface. Certain turfgrass varieties produce more thatch and must be verticut or dethatched to maintain good health. This action benefits both the lawn grass and the soil by allowing the soil to accept nutrients that would otherwise be trapped within the thick thatch layer.
Nutrients “locked” within thatch layer can also cause shallow rooting because nutrients and soil amendments don’t infiltrate downward through the root zone profile. Shallow roots hinder growth, and any modification that allows downward nutrient movement into the root zone benefits both the soil and lawn grass.
5. Building a Solid Fertilization Program
The absence or excess of nutrients plays a role in the success of lawn grass growth. The essential nutrients must be present so the lawn can function fully. Essential macro and micronutrients work in coordination to supply the soil with building blocks to maintain a healthy environment for growth. Applying fertilizers without knowing what the turfgrass needs is a blind ambition that could harm the soil and the lawn grass.
Fertilization programs and applications should be based on scientific data from soil testing results. Liquid fertilization is a sure way to supply the nutrients needed due to the immediate availability of nutrients in the soil.
6. Liquid Soil Loosener for Standing Water
Improving internal drainage and infiltration within the soil is the primary goal of lawn grass management. Due to anaerobic conditions, saturated root zones are less likely to produce healthy results. Anaerobic conditions occur when the amount of oxygen used by soil exceeds the amount of oxygen diffused into the soil. This can happen when the soil has little to no available oxygen, and the oxygen in the soil pores is replaced by water.
Soil Loosener can promote the drainage of standing water, and conditions compacted soil.
It's The Soil That Matters
The success of lawns heavily depends on soil and its versatile functions. Effective internal drainage is essential for water acceptance and maintaining infiltration and percolation rates, ensuring water penetrates deep into the root zone. This requires proper soil texture with soil particles' correct shape and size. Applied nutrients must travel downward to be absorbed by the root system. Soils with a reduced or slow infiltration rate can become toxic with salt buildup in the upper layers of the soil and thatch.
Cultural practices such as aeration, verticutting and dethatching, topdressing, and applying chemical additives designed to break down soil and create additional capillary space improve the soil. Soil health maintenance is a continuing process that must be repeated each growing season. Soils can also be modified to adjust pH within optimum ranges by adding limestone or elemental sulfur. Proper pH within the soil allows applied and stored nutrients to be absorbed for growth, energy, and healing. Ultimately, soil serves as the lifeline for the success of all turfgrass plants. Maximizing its benefits through soil testing, cultural practices, and amendments fosters a positive growing environment.
